The just-wrapped fourth season of Showtime series "The Affair" focused on the disappearance of a major character, but it's the behind-the-scenes drama surrounding the actress who played her that's making headlines now.

Ruth Wilson, who was one of the four main stars of the series since the beginning, has officially left the show, after her character, Alison, was found dead in the episode that aired on August 5. After that major revelation, showrunner Sarah Treem said that Wilson had requested to be written off the series, something that the actress confirmed.

But the reasoning behind that decision was and remains unclear. In an interview with "CBS This Morning" on Thursday, Wilson briefly touched on the subject -- but added more mystery than clarity. (Skip ahead to the 3:45 mark.)

"I did want to leave, but I'm not allowed to talk about why," Wilson told host Gayle King when asked about her exit.

When King then referenced an earlier interview in which the actress discussed the lack of pay parity with co-star Dominic West -- despite the fact that Wilson won a Golden Globe for her role back in 2015 -- Wilson insinuated that that was not the reason why she left.

"I've never complained to Showtime about pay parity," she said.

The subject was abruptly changed after that, leaving a lot unsaid. Whatever the truth is, Wilson doesn't seem eager to discuss it. That "not allowed" phrasing is certainly a curious choice of words. It's obvious that there's a much bigger story waiting to be told, but it's anyone's guess when such a tale might become public knowledge.

For its part, Showtime insists that there's nothing to the story other than Alison's story had come to its natural conclusion. The premium cable outlet issued a statement in response to Wilson's comments on Thursday afternoon:

“We can’t speak for Ruth, but heading into season four everyone agreed the character’s story had run its course. Ultimately, it felt like the most powerful creative decision would be to end Alison’s arc at the moment when she had finally achieved self-empowerment,” Showtime said. “The impact of her loss will be felt as the series concludes next season. We thank the many fans who embraced the character of Alison and especially thank Ruth for her indelible work over the past four seasons.”

In any event, "The Affair" has been renewed for a fifth and final season,  without Wilson on board. It's set to premiere sometime in 2019.

[via: CBS This Morning, Variety]